Heat-treating apparatus



July 11, 1950 F. o. HESS ET AL HEAT-TREATING APPARATUS 8 Sheets-Sheet 1 Filed Sept. 18, 1946 fill/bald 1 1m,

WHTTUHNY F J"J w/r/vsss July 11, 1950 F. 0. HESS ETAL 2,515,086

HEAT-TREATING APPARATUS Filed Sept. 18, 1946 8 Sheets+Sheet 2 w Mam a Fr adH wrrlvsss a) (U- gym 3 July 11, 1950 F. o. HESS ET AL. 2,515,086

HEAT-TREATING APPARATUS Filed Sept. 18, 1946 8 Sheets-Sheet 3 5}, M 13. F w/TNESS fiI TTQ/P/YEY July 11, 1950 F. o. HESS ETAL 2,515,086

HEAT-TREATING APPARATUS Filed Sept. 18, 1946 8 Sheets-Sheet 4 NVENTO/FS WITNESS BY TG/PNE r July 11, 1950 F. o. HESS E'AL HEAT-TREATING APPARATUS 8 Sheets-Sheet 5 Filed Sept. 18, 1946 -INVEIVTUI?$ VV/ TNESS July 11, 1950 F. o. HESS EI'AL HEAT-TREATING APPARATUS Filed Sept. 18,, 1946 8 Sheets-Sheet 6 W/TNESS July 11, 1950 F. o. HESS E'I'AL HEAT-TREATING APPARATUS 8 Sheets-Sheet 7 Filed Sept. 18, 1946 Y E N J W R W T m LB A T ow D H K W o M ww /w a 7 W N 7 M WITNESS 7 r July 11, 1950 F. o. HESS EI'AL 2,515,086

HEAT-TREATING APPARATUS Filed Sept. 18, 1946 8 Sheets-Sheet 8 d INVENTORS 3 H044 BY Wm '34 Tim y .7 W HM ill 08/1 57 Patented July 11, 1950 HEAT-TREATING APPARATUS Frederic 0. Hess, Fred Maud, and William B.

Troupe, Philadelphia, Pa., assignors to Selas Corporation of America, Philadelphia, Pa., a corporation of Pennsylvania Application September 18, 1946, Serial No. 697,624

This invention relates to heat treating apparatus, and more particularly to an improved machine for continuously and automaticallyheat treating a number of like or similar metallic pieces in rapid succession. I

A principal object of the invention is to provide heat treating apparatus for continuously and automatically heat treating a number of similar or like metallic work pieces in rapid succession which will be reliable and sensitive in operation and which will not readily get out of adjustment, so that substantial uniform heat treatment of the work pieces is effected. This is accomplished by providing a heat treating machine having a number of spaced apart operating stations at which the work pieces are heated and cooled, and a rotatable carriage having a plurality of spaced apart work supporting fixtures for the work pieces. Suitable mechanism is provided for intermittently moving the carriage at definite intervals of time in such a manner that the carriage is alternately raised andlowered as well as rotated to move each work supporting fixture from one station to a succeeding station in a path Of movement which includes an initial increment of movement which is generally up ward and a final increment of movement which is generally downward.

More specifically, the carriage is mounted on and rotatably supported by a vertical post which is intermittently raised and lowered rapidly, and a suitable cam device is provided which, during such upward and downward movement of the post, is capable of imparting a turning or angular movement to the carriage to carry the work supporting fixtures from one station to a sucseeding station in the manner just described. In

the embodiment of the invention disclosed herein, the cam device includes a cylindrical cam member fixed to the carriage which is formed with a race and a stationary cam follower which cooperates with the race. The cam race is of such shape that when the vertical post and carriage mounted thereon are alternately raised and lowered, movement is imparted to the carriage to carry the work supporting fixtures from one station to a succeeding station in a path of movement which includes an initial increment of movement which preferably is more or less straight upward and a final increment of movement which preferably is more or less straight downward.

Further, the cam race of the cam member is of slEh shape that the carriage and work fixtures 13 Claims. (01. 266-4) tion to a succeeding station and cannot move backward. Moreover, a cam race is provided for the cam device which permits the carriage to turn freely to carry the work supporting fixtures from one station to a succeeding station when the vertical movement of the carriage is reversed after being raised a definite distance by the post upon which it is mounted. In other words, when the carriage is alternately raised and lowered the carriage does not come to a complete stop when its direction of vertical movement is reversed; and the angular momentum imparted to the carriage during its upward movement is advantageously utilized at the moment its direction of vertical movement changes to continue the desired movement of the carriage until the work supporting fixtures reach the stations to which they are being carried.

In accordance with the invention, the work pieces to be heat treated are moved from a work loading and unloading station to one or more heating stations and to .a quench station from which the work pieces are returned to the work loading and unloading station. In the preferred embodiment of the invention disclosed herein, a cooling station is also interposed between the quench station and the work loading and unloading station; By carrying the work supporting fixtures from each station to a succeeding station in a path of movement in which the initial increment of movement is generally upward and the final increment of movement is generally downward, the one Or more heating stations may be formed to more Or less completely encircle the work pieces when the latter are positioned therein. By advancing the work pieces to the same identical position at the one or more heating stations in the manner just described and accurately timing the heating periods by controlling the intermittent movement of the carriage, successive work pieces are accurately heated in an identical manner.-

Likewise, by reason of the particularmanner in which the work pieces are carriaged from one station to a succeeding station, the quench station may include a suitable spray device which is submerged in a body of quench liquid and adapted to encircle successive work pieces carried .to the quench station. By delivering quench liquid under pressure to such spray device, quench liquid can be effectively applied to particular surv faces of the heated work pieces to promote rapid and uniform cooling of each work piece in the same manner as other work pieces.

thereon are always moved forward from one staa In order to controlaccuratel the intermittent movement imparted to the rotatable carriage, suitable mechanism and associated control is provided for intermittently raising and lowering the vertical post upon which the carriage is mounted. This may be accomplished by providing a hydraulic cylinder whose, cylinder rod serves as the vertical post to which the carriage is fixed, and by controlling the supply of hydraulic fluid under pressure to the hydraulic cylinder to I raise and lower the cylinder rod in definite intervals of time, each upward stroke and subsequent downward stroke of the cylinder rod taken together constituting a complete cycle of movement necessary to carry the work supporting fixtures from one station to a succeeding station.

In order to promote uniform and rapid heating and cooling of the work pieces atthe heating and quench stations, suitable driving mecha nism is mounted on the carriage for turning the work supporting fixtures. In order to facilitate the removal of heat treated work pieces from the fixtures at the work loading and unloading station and the positioning of fresh work pieces on the fixtures at that station, provision is made for reducing the turning movement of the fixtures at the work loading and unloading station. Preferably, the fixtures at the work loading and unloading station are brought to a complete stop anddisconne'cted from the driving mechanism to facilitate the removal of heated work pieces and the positioning of fresh work pieces on the work supporting fixtures.

In addition, mechanism may be embodied in 4 partly broktn away and in section, to illustrate the construction of the apparatus more clearly;

Fig. 3 is a horizontal plan view of the apparatus taken at line 3-3 of Fig. 2;

Fig. 4 is an enlarged vertical sectional view. taken at line 4-4 of Fig. 3, of one of the heating units which serves as a heating station;

Fig. 5 is a horizontal view, takenat line 5-5 of Fig. 2, to illustrate the relative positions of the work loading and unloading station, heating statlons, quenching station and cooling station;

Fig. 6 is a horizontal sectional view, taken at line 6-6 of Fig. 2. to illustrate details of the heat treating apparatus; I

Fig. 7. is an enlarged fragmentary plan view of the rotatable work supporting carriage seen in Figs. 1 to 3;

Fig. 8 is an enlarged side elevation, partly broken away and in section, of one of the radially extending arms of the work supporting carriage;

Fig. 9 is an enlarged plan view, partly in section, of the cylindrical cam member of the work supporting carriage for indexing the rotating the heat treating machine of the invention to effect so called time quenching" of the heated work pieces. To this end the work supporting fixtures are vertically movable on the carriage and suitable mechanism is provided at the quench station whereby each work supporting fixture moved to that station may be raised independently of the other fixtures after a predetermined interval of time to lift each quenched work piece out of the body of quenching liquid. Although the quenched work pieces are independently raised out of the quench liquid at the quench station, such lifting of the quenched work pieces during the intervals of time the carriage is stationary does not affect the operations being accomplished at the other stations; and, when the carriage is again moved to carry the work pieces from one station to a succeeding station, the work piece at the quench station is automatically moved from its raised position at that station to the next succeeding station.

' In order to protect parts of the machine from over heating, provision is made for cooling those parts subjected to the high temperature heat produced at the one or more heating stations. Thus, the parts of the carriage which are closely adjacent to the heat sources at the one or more heating stations are preferably cooled by a suitable cooling liquid. Likewise, the cylindrical cam member is preferably shielded from the one or more heating stations by a hollow wall through which a cooling liquid is circulated.

The invention, together with the above and other objects and advantages thereof, will be more fully understood from the following description taken in conjunction with the accompanying drawings forming a part of this specification, and of which:

Fig. 1 is an elevation view of heat treating apparatus embodying the invention;

Fig. 2 is a view generalLv similar to movement of the carriage;

Fig. 10 is a vertical sectional view of the cylincomprising a stationary base structure Ill above which is disposed a rotatable carriage structure or turntable ll having five radially extending arms I 2. From the outer ends of the arms I! depend work supporting fixtures i4 whose lower ends are formed to support work pieces I5 adapted to be heat treated.

The rotatable carriage II is arranged to move each fixture l4 and work piece supported thereon from a loading and unloading station it successively to first and second heating stations I! and I8, a quench station It, and a cooling station 20 back to the loading and unloading station it. When the work-pieces I! are moved from each station to the next succeeding station by the rotatable carriage II, the carriage initially moves vertically upward for a definite distance and then begins to move angularly about its axis, such angular movement of the carriage being accompanied by further upward vertical movement thereof followed by downward vertical movement thereof as each fixture it approaches the station to .which it is being moved.

When the carriage II has turned or rotated about its axis such a distance that the fixture is at a definite position over the station to which it is being moved, the carriage ll finally moves vertically downward and comes to a stop. After a definite interval of time the carriage Ii again turns about its axis to move each work piece to the next succeeding station until it reaches the loading and unloading station it where it is removed.

Each work piece IE is rotated continuously by its supporting fixture it after it leaves the loading and unloading station it until it returns to that station. At the loading and unloading station the fixtures I4 do not rotate and remain stationary to facilitate the removal of heat treating work pieces therefrom and the positioning on the fixtures of fresh work pieces to be heat treated.

As shown in Fig. 2, suitable framework 2| including a centrally disposed box-like section 22 and a number of horizontal sections 2'! extendin radially outward therefrom, is adapted to be supported on a foundation 24. Riser sections. extend upward from the horizontal sections 24 and serve as structuralsupports for parts of the heat treating apparatus to be described presently.

A sheet metal shell 26 of cylindrical form is provided about the framework 2| and fixed thereto in any suitable manner, as by welding, for example. The side wall of the shell 28 may be provided with removable screened panel sections 21, as shown in Fig. 1, to provide adequate ventilation of the interior of the shell and obtain easy access therein.

The rotatable carriage H is supported and journaled at 28 at the extreme upper end of an elongated hydraulic cylinder rod 29 having a piston 30 intermediate the ends thereof which is vertically movable in a cylinder 3|. The cylinder 3| at its opposite ends is provided with apertured closure members 32 through which the rod 20 passes. Packing glands 33 are provided for the rod 29 at the closure members {2 to prevent leakage of fluid from the interior of the cylinder 3|. Such fluid is alternately introduced under pressure to opposite ends of the cylinder 3|, as shown in Fig. 13 and described more fully hereinafter, to cause the rod 29 to move alternately upward and downward and impart the desired rotatable movement to the carriage The lower end or closure member 32 of the cylinder 3| is supported upon the top of the hollow box-like section 22 of the framework 2|. Such support for the cylinder 3| is at an adequate height to permit the bottom part of the rod 29 to move downward to its lowermost position, as shown in Fig. 2.

The carriage may be supported and journaled at 28 in any suitable manner, as by a combination thrust and radial roller bearing, for example; and a pan 34 fixed to the rod 2! and movable therewith may be provided to hold a body of oil in which such bearing is always immersed.

' The rotatable carriage comprises spaced apart ring-shaped plates 35 to which are secured at 36 the flanged inner ends of the radial arms i2, as shown in Figs. '7 and 8. Each arm I2 includes structure providing a hollow bottom 31 and an upstanding hollow side wall 38 communicating therewith which is U-shaped in horizontal section. The hollow bottom 31 of each arm |2 is formed with openings 39 and ll midway between the parallel sides of the hollow side wall 38 and also a solid partition 4| in alignment with such openings to divide the hollow bottom into two sections. By providing the partitions II, each arm i2 is formed with opposing L-shaped hollow chambers which communicate with each other only at the extreme outer end of the arm and at the bend of the hollow side wall II, as best shown in Fig. 8.

Hence, the radial arms I! are formed with the hollow walls as just described and a suitable cooling liquid, such as water,- for example, is circulated therethrough in order to prevent overheating of the outer parts of the arms I! when the latter are disposed above the heating stations As best shown in Figs. 2 and 5, the cooling liqquid is delivered from a suitable source or supply through piping 42 to the lower end of a riser pipe 43. As seen in Fig. 2, the riser pipe 3 extends to a height above the carriage ii and at its lower end is fixed in any suitable manner to the top of the shell I. The upper end of the riser pipe I! is connected to one end of a horizontal pipe ll, the opposite end of which is connected to a. vertical pipe 48 intermediate the ends thereof.

To provide a rigid support for the pipes 43, M and l and maintain the latter accurately positioned above the carriage ii, for reasons which will be explained presently, additional vertical pipes It and I! are mounted'on the top of the shell 28 at each side or the pipe 43, as shown in Figs.1, 2, 3 and 5. The upper ends of pipes M and 41 are connectedto the outer ends oi horiaontal pipa '48 and 4!, the inner ends of which are secured, as by welding, for example, to the horizontal pipe II at a region adjacent to. the vertical pipe 45. The pipes l8, l1, l8 and 0 provide a rigid reinforcing framework for the cooling liquid supply piping, it being understood that cooling liquid only flows through the pim ll, ,4 and- Hence, the horizontal pipes ll and I8 are blocked 011 in any suitable manner at their inner ends, at the connection of these pipes to the horizontal pipe 48, to prevent how of cooling liquid into the pipesservlng only as reinforcing framework.

As shown in Figs. 1 and 2, the upper end ofthe vertical pipe 45 is closed and cooling liquid is discharged from the lower open end thereoi into an annular-shaped tank or reservoir 50 mounted inany suitable manner to the top rlng-shapedplate cf the carriage ll.

The cooling liquidfiows by gravity from the bottom of the reservoir 50 through five flexible conduits (not shown) whose lower ends are adapted to be connected to suitable inlet connections 5|, each of which is associated with one of the radial arms 12, as best shown in Figs. '7 and 8.

The cooling liquid delivered to each radial arm I! through the inlet connection 5| associated therewith passes into the hollow bottom 31 of the L-shaped chamber at one side of the partition ll therein. The cooling iiquidmust flow toward the outer bend of the-side wall 3! and return through the L-shaped chamber at the opposite side of the partition 4| before being discharged through an outlet connection 52. Moreover, by providing the outlet connections 52 at the extreme upper ends of the side walls 31, as seen in Fig. 8, the hollow walls of each radial arm M will always be completely filled with cooling liquid.

The cooling liquid overflows by gravity from the radial arms I! through the outlet connections 52 into the upper ends of downwardly extending tubes 53 communicating therewith. As best shown in Fig. 2, each tube 53 passes through an opening in the bottom carriage plate 35 and extends downwardly alongside the pan 3|. The lower ends of the tubes 53 extend into an annularshaped trough El supported on the box-like section 22 of the framework 2|.

When the carriage turns about its axis to move each work supporting fixture H from one station to a succeeding station, the carriage |i moves vertically as well as angularly, as mentioned above and described more fully hereinafter. With such movement of the carriage II, the tubes 53 not only travel about the trough 5| but also move vertically therein. The cooling liquid is discharged to waste from the bottom of the trough 5| through suitable piping 55 which extends outside the shell 26, as best shown in Fig. 6.

The work loading and unloading station It is i and rotatable therewith.

best shown in Flgszl and 5. In the present embodiment of the invention the work pieces I! by way of example are of annular form and shown as ring gears having teeth at the outer peripheral surface thereof. The work supporting fixtures It in this instance are provided with suitable members it having three spaced apart radially extending arms to fiicTvide a three point support for the work pieces 15. The members it are formed of suitable alloy capable of withstanding high temperatures and provide an arrangement whereby an operator can quickly remove such work pieces I! from and position the work pieces on each member 56 when it moves to the work loading and unloading station It.

To eflect rapid and uniform heating of the 1 work pieces at the heating stations 11 and II, as

will be described hereinafter, it is desirable to rotate the work pieces. providing suitable mechanism for rotating the work supporting fixtures it immediately after each work piece l5 leaves the work loading and unloading station it until it returns to that station. To this end each work supporting fixture 1 It comprises a vertically disposed rotatable spin- This is accomplished by dle 51 to the lower end of which one of the work supporting members it is secured.

As best shown in Fig. 8, the upper part of each spindle 51 is keyed in a bushing 58 through which it extends. The bushings 58 are journaled at their lower ends at 59 at the regions of the openings 40 in the hollow bottoms of the radial arms l2; and at their upper ends in suitable bearings I fixed to cover plates 6| provided at the tops of theradial arms l2. The cover plates ll are formed with enlarged openings 62, as seen in Fig. '1, to provide access to the housings formed in the radial arms.

The spindles 51 are vertically movable in the bushings it and formed with enlarged heads 63 which engage the upper parts of the bearings to limit the extent of their downward vertical movement. To the bottom portion of each bushing. 68 is fixed a collar 64 having teeth at the top edge thereof. About each bushing 58 is also 1 provided a freely rotatable sleeve 85 having a shoulder 68 intermediate the ends thereof and teeth at its bottom edge adapted to mesh with the teeth at the top edge of the collar 64.

A grooved pulley 61 is fixed to each sleeve 65 The pulleys 61 at the outer ends of the radial arms I! are driven by endless belts 68 from a number of sheaves 69 fixed to the lower end of a vertical shaft 10 which is in alignment with and above the hydraulic cylinder rod 29. An idler pulley 1| i provided for each belt 68 to adjust the tension of the belts.

As shown in Figs. 7 and 8, the idler pulleys II are eccentrically mounted at the lower ends of hollow sleeves 12 which are bolt connected at 13 to the top ring-shaped plate 35. By shifting the idler the shaft 10 is driven through speed reducing mechanism 14 from an electric, motor 15, such mechanism being mounted at the opening in the top ringshaped plate 35 and the motor 15 in tum being mounted on the casing of the speed reducing mechanism.

Since the carriage structure U moves both anguiarly and vertically about its axis, suitable provision must be made for energizing the motor :18. This may be accomplished, 'as shown in Fig.

2, by providing a plate or disk 18 formed of suitable insulating material, such as Bakelite, for example, which is carried by a supporting bracket 11 at the top of the motor 15 and rotatable and vertically movable with the latter. In the top surface of the plate 18 are embedded a pair of annular slip rings connected by conductors" to the motor 15. A pair of conductors 18, adapted to be connected to a source of electrical supply, are secured to a pair of brushes 8!), each of which is adapted to bear and ride on one of the slip rings. The brushes to are suitably mounted in a plate II which is formed of insulating material and rotatably mounted on the plate 18. Hence, the motor 15 is energized from the source of electrical supply through the conductors 19, brushes 80. the slip rings over which the brushes ride and the conductors 18.

In order to permit the plate 8i to move vertically with the carriage ll, between the solid and dotted line position of the parts shown in Fig. 2 and at the same time prevent turning movement thereof, that plate is rigidly secured to the inner surface of a cup-shaped shell or housing member 82 having a triangular-shaped bracket 83 projecting outwardly therefrom. The extreme outer end of the bracket 83 is notched and positioned closely adiacent to the vertical pipe 45, as shown in Figs. 2 and 3. The notched bracket 83 freely rides up and down along the pipe 45, thereby permitting the brush plate 8| to move vertically. However, the notched bracket 83 prevents turning of the plate 8| about its axis even though the latter is rotatably mounted on the insulating plate 18 carried by the motor 15. I

In view of the foregoing, it will now be understood that the sheaves 69 on the shaft 10 are driven through the speed reducing mechanism 14. by the motor 15, and that the grooved pulleys 61 at the outer ends of the radial arms l2 are driven from the sheaves by the endless belts 68.

By providing teeth at the top and bottom edges of; each collar 84 and sleeve 85, respectively, these parts serve as cooperating elements of a-clutch, whereby the freely rotatable pulleys 61 and sleeves ii to which such pulleys are fixed drive the collars 6i and bushings 58 'fixed thereto and to which bushings the spindles 51 are keyed.

The spindles 51 and work pieces l5 carried thereby are driven continuously after each spindle leaves the work loading and unloading station I 6 until it returns to that station. Each spindle 51 is disconnected from the driving'mechanism just described when it moves to the work loading and unloading station I8 to facilitate the removal of a work piece from and the positioning of another work piece on each work supporting member 56.

As best shown in Figs. 1, 2 and 5, this is accomplished by providing a C-shaped hollow shell 84 which is disposed about the hydraulic cylinder rod 29 and is secured atits bottom edge at 84a to the top of the shell 26 of the base structure Ill. Directly opposite the loading and unloading station It the C-shaped shell is formed with an cally upward and downward, respectively. Hence, as one of the radial arms I2 moves to the work loading and unloading station I8, the carriage II turns such an angular distance that the roller 88 on the radial arm moves to a position directly above the tab; and, when the carriage II moves vertically downward for the flnal portion or increment of the indexing movement, the roller 88 moves downwardly against the tab 85 and rides on the sloping outer surface thereof.

As best shown in Fig. 8, the rollers 88 are journaled at the lower forked ends of the short arms of L-shaped members 81 pivoted at 88 within the housings of the radial arms I2. The short arms of the L-shaped members 81 project downwardly through the openings 39 in the hollow bottom walls 31, and the long arms thereof extend toward the spindles 51. Each L-shaped member 81 at the outer end of its long arm is provided with a U-shaped yoke 89 in each arm of which is journaled a roller 98.

After each radial arm I2 leaves the loading and unloading station I8, the L-shaped member 81 is in the position shown in Fig. 8. In such position the long arm of the L-shaped member 81 rests on a stop 9I and the rollers 98 at the yoke 89 are below the shoulder 88 of the sleeve 85 and out of engagement with all parts of the driving mechanism for the spindle 51.

However, when each radial arm I2 moves to the work loading and unloading station I8 and the roller 88 associated therewith rides on the tab 85, the short arm of the L-shaped member is pushed or kicked radially outwardly about its pivot 88, thereby raising or lifting the yoke 89 at the end of the long arm. When this occurs, the rollers 98 at the yoke 89 engage the lower face of the shoulder 88 to raise the hollow sleeve 85, thereby disengaging the teeth at the bottom edge of the sleeve from the teeth of the collar. The' separation of the collar 84 and hollow sleeve 85 disengages the spindle 51 from its driving mechanism to bring the spindle 51 at the work loading and unloading station to a stop.

When the radial arms I2 are again moved from each station to a succeeding station, the roller 88 associated withthe radial arm I2 at the work loading and unloading station l8 leaves the tab 85; and, due to force of gravity, the heavier long arm of the L-shaped member 81 moves downward against the stop 9|, whereby the rollers 98 on the yoke 89 also move downward to permit the hollow sleeve 85 to engage the collar 84 and again drive the spindle 51.

From the work loading and unloading station I8 the work pieces I5 are moved successively to the first and second heating stations I1 and I8. As best shown in Fig. 3, identical heating units 92 are provided at both heating stations. Referring more particularly to Figs. 2 and 4, each heating unit 92 is formed to provide an open work receiving space 93 of cylindrical form having a bottom 94 and upstanding side wall 95 formed of refractory material. The heating units 92 are mounted on metallic framework 98 fixed to the top of the shell 26 of the base structure I8. In order to prevent overheating of the shell 28, the framework is embedded in suitable refractory brick work 91 to shield the shell 28 thermally from the heating units.

The cylindrical side walls 95 of the heating units are formed to provide ring-shaped combustion spaces 98 of cross-sectional shape illustrated in Fig. 4. The combustion spaces 98 are provided with restricted outlets 99 for directing high temperature heating gases into the work 10 receiving spaces 98. The restricted outlets 99 extend about the entire peripheries of the side walls 95 so that, when the work pieces I5 arev lowered in the work receiving spaces 93 and come to a stop, the elongated outlets 99 are directly opposite the parts of the work pieces to be heated and the heating gases will impinge such parts. The combustion spaces 98 are provided with inlets I88 in the form of screens and through which a combustible gaseous mixture is discharged from a hing-shaped manifold I8I flxed to the bottoms of the refractory side walls. Each screen I88 may comprise a stack of thin plates of refractory material disposed one against the other and formed with vertical slots at the.

faces thereof to form a multiplicity of tiny passages to subdivide the gaseous mixture entering the combustion space 98 into a plurality of tiny gas streams.

The manifolds I8I are provided with inlets I82. to which are connected conduits I89 each havin a valve I84 connected therein. As shown in Fig. 3, the conduits I88 for the heating units 92 are connected to a common supply pipe I85 having a main valve I88, such pipe being adapted to be connected to a source of supply of a. suitable combustible gaseous mixture.

when the heating units 92 are relativel cool and at a low temperature, the combustible gaseous mixture supplied thereto passes through the manifolds 'I8I, -screens I88 and spaces 98 from which it is discharged through the restricted outlets 99. The combustible gaseous mixture is initially supplied to the heating units 92 at a relatively low pressure which may be equivalent to a pressure corresponding to about 5 or 6 inches of water column, for example, so that the gaseous mixture discharged from the spaces98 can be ignited to produce and maintain flames at the outlets 99.

When a flame is being maintained at the outlet 99 of each heating unit, the pressure of the gaseous mixture supplied to the heating units may be momentarily reduced sufllciently to cause the flame of backfire through the outlet 99 onto the apertured screen I88 in the space 98. When this occurs a plurality of flames are produced and maintained at the discharge ends of the small passages in the screens I88.

When the flames are being maintained within the spaces 98, the pressure of the gaseous mixture supplied to the heating units 92 may then be increased. After a short interval of time, the flames maintained at the screens I88 effect such heating of the inner refractory wall surfaces of the spaces 98 that these surfaces are heated to a high incandescent temperature. The heating of the inner refractory wall surfaces to a highly incandescent condition and the radiant heat therefrom promotes substantially complete combustion of the gas mixture in the combustion spaces 98 before the mixture reaches the outlets 99. From the outlet 99 of each heating unit 92 is discharged a high velocity jet or stream of heated gases at a temperature nearly equal to the temperature in the combustion space 98 and consisting substantially entirely of heated products of combustion.

In heating units of the type just described, the heated products of combustion are dis-- charged from the combustion spaces 98 through the restricted outlets 99 at an elevated temperature ranging from 2708 F. to 2908 .F. and higher when a combustible gaseous mixture of air and ordinary gas, such as city gas having a B. t. u.

rating of about 550 B. t. u. per cubic foot, for example, is supplied at a pressure in the neighborhood of three pounds per square inch. The heated gases in such case are discharged from the heating units 92 at an average velocity of about 750 feet or more per second and at a maximum velocity of about 1000 feet or more per second.

By reason of the high temperature developed at the heating stations I! and I8, it is desirable to cool the heating units 92 to prevent overheating of the manifolds I Ill and other parts of the apparatus adjacent thereto. As shown in Fig. 4, this is accomplished by providing hollow Jackets I01 and I08 of cylindrical form at the top and outer peripheral surface of each refractory side wall 9!. Further, a hollow jacket I08 of cylindrical form may be provided in the refractory side wall 95 adjacent to the refractory bottom 94 and manifold IIII.

A suitable cooling liquid, such as water, for example, is circulated through the hollow jackets I", I0. and I09. To this end the Jacket I01 is provided with inlet and outlet openings H and III, the Jacket I 08 with inlet and outlet openings H2 and H3, and the jacket I09 with inlet and outlet openings Ill and H5. The hollow jackets I01, I 08 and I09 are partitioned in any suitable manner (not shown) between the inlet and outlet openings to cause the cooling liquid to circulate about the jackets; and suitable connections (not shown) may be provided to deliver cooling liquid to the jackets and discharge such cooling liquid therefrom to waste.

It has already been explained that the radial arms I2 are of hollow construction and cooling liquid is circulated therethrough in order to avoid overheating of the arms I2, particularlywhen the radial arms are moved to the heating.

stations I! and I8. In addition, the c-shaped shell 84 also is desirably of hollow construction, as shown in Fig. 2, and provided with inlet and outlet openings (not shown) adjacent to the bottom and top edges of the shell and at the opposite ends thereof for circulating a cooling liquid therethrou h. The c-shaped shell 04 shields the cylinder rod 29 and other parts of the heat treating apparatus from the high temperature heat produced at the heating stations I1 and I8. Hence, by circulating coolin liquid through the c-shaped shell 84, heat is effectively taken u by the cooling liquid and obiectlonable overheating of the parts of the heat treating apparatus is avoided.

By providing the heating station I1 and It the work pieces I5 are heated to the desired elevated temperature in two stages. the initial heatin: of the work pieces being accomplished at the heating station I I and the final heating being accomplished at the heating station I t. From the second heating station I8 the radial arms l2 of the carriage II carry the heated work pieces I! to the quench station I9.

As shown in Figs. 1, 2, 3 and 5, the quench j station I 9 is located at one end of an arcuate shaped tank H8 provided at the top of the shell 28. The tank H6 is formed with an opening in the top and adapted to hold a body of quenching liquid, such as oil, for example, to the level III indicated in Fig. 2. When each work piece l5 moves to the quench station I9 and comes to a stop beneath the liquid level III in the tank II6, the work piece is positioned within a hollow ring or manifold 8 which is supported within the z tank by a plurality of spaced brackets lit, as shown in Figs. 2 and 5.

The ring 8 is provided with a number of small openings distributed about the inner peripheral surface thereof for discharging the quench liquid under pressure to the outer peripheral surfaces of the work pieces which have been moved to the quenching station I8. By discharging the quench liquid from the ring. I I8 in this manner, vigorous circulation and turbulent movement of the quench liquid is promoted at regions closely adjacent to the work pieces I5 to effect rapid cooling, especially at the outer peripheral surfaces thereof. Further, the quench liquid discharged through a number of small openings formed in the ring IIB effectively breaks up any vapor film tending to form at the surface of the work pieces when the latter are immersed in the body of quench liquid at the quench station I9.

In the embodiment of the invention illustrated, provision is made for recirculating and cooling the quench liquid. As best shown in Figs. 2 and 6, the quench liquid passes through an outlet I20 provided at the upper end of a conduit I2I whose lower end is connected to the inlet of a pump I22 arranged to be driven by an electric motor I23. The pump I22 and motor I23 are mounted on the framework 2| within the shell 26 directly beneath the tank H6. The quench liquid is discharged from the pump outlet through a conduit I24 to a sediment separator I 25 and thence passes from the latter through a conduit I28 into one end of a heat exchanger I21.

-The quench liquid flows in one path of flow in the heat exchanger in thermal exchange relation with and out of physical contact with a cooling liquid, such as water, for example, which enters through a supply conduit (not shown) to an inlet I28 and is discharged to waste through a conduit (not shown) connected to an outlet I29. From the heat exchanger the cooled quench liquid passes through a riser conduit I30 which extends upwardly in the tank H6 and is connected at its upper end to the ring I I 8.

In order to adJust the pressure at which the quench liquid is discharged from the openings in the ring II8, a pressure relief valve I3I may be I connected in the conduit I30. When the pressure of the quench liquid in the conduit I30 exceed a predetermined pressure, determined by the adjustment of the relief valve I3I, quench liquid is discharged through the valve I3I diregtly into the tank H6 and by-passes the ring II In certain heat treating and hardening operations, it may be desirable to effect an initial quick cooling of the heated work pieces IS in the quench tank I I8 and thereafter effect further slow air cooling of the work pieces. Cooling of heated work pieces in this manner is often referred to as time quenching and employed where it is desired to utilize the residual heat in the work pieces to reheat the heat treated parts to a temperature approaching that used for tempering. Suitable mechanism is provided in the embodiment of the invention shown to eflect such initial quick cooling of the work pieces in the quench tank 6. Such mechanism includes a hydraulic cylinder I32 which is disposed in the tank IIB beneath the ring H8 and in alignment with the spindles 51 when the latter are successively moved to the quench station I9, as shown in Fig. 2.

As will be described more fully hereinafter, a cyl nder rod I33 of the hydraulic cylinder I32 is arranged to move upwardly in a definite intervaloftimeaftereachworkpiece IIcomestoa stoplnthequenchtank II. Whenthisoccurs the spindle i1 and work piece supported thereon, which is positioned at the quench station ll, moves upwardly such a distance that the work piece is well above the liquid level III and out of the body of quench liq d.

Since the spindles 51 are keyed to the bushings l3attheouterendsoftheradialarms I2,each work piece at the quench station I3 can be moved upwardly independently of the work pieces at .the other stations; and, when the carriage It is thereafter raised or turned about its axis to advance each work piece to the next succeeding station, the carriage in its upward movement will lift the spindle from its raised position at the quench station I! when the enlarged head .3 thereof engages the bearing II. After the spindle II at the quench station I! is picked off the upper end of the cylinder rod I33, the latter then moves downwardly, as will be described presently. to permit the succeeding work piece moving to the quench station I3 to come to a stop beneath the liquid surface level III directly-opposite and within the annularring III.

The work pieces I are moved by the carriage II from the quench station I! to what may be referred to as the cooling station II. The work pieces I! come too stop at the cooling station 2| against a plate I34 provided on a pan I35 partiallycoveringtheendofthetank IIi nearest to the work loading and unloading station II, as best shown in Figs. 1, 3 and 5. Hence, whilethecarriage II actstobringcertainofthe work pieces I5 to one level at the heating stations Iiand I'Iandinsuchcasetheenlarged heads 63 of the spindles 51 engage the bearings G3, the spindle 51 at the cooling station is in araisedpositionandrestsonthepan |34and theenlargedheadilthereofisinaraisedpositionwithrespecttothebearingilasbestshown in Fig. l. The pan I35 slopes downwardly to permit quench liquid dripping from the work piece I! resting on theplate I34 to flow by gravity into the tank II.

The work piece l5 move fromthe cooling station Ilbacktotheworkloadingandunloading station It at which station the work pieces come to a stop and are not rotated by the spindle 51, as previously explained. At the work loading and unloading station I, each heat treated work v piece is removed from its supporting member 5i and a fresh work piece is positioned thereon by an operator.

In orderto collect quench liquid dripping from the work pieces at the work loading and unloading station II, that station is provided with a cupshaped screen I36 fixed at an opening in the top of the shell I, as best shown in Fig. 5. Beneath the screen I3 is podtioned a vessel I31, as best shown in Fig. 6, from which quench liquid flows through a conduit I33 into an upstanding vertical cylinder I33 in which the quench liquid is collected. After the cylinder I33 becomes filled with 14 Hence, quench liquid dripping from the work pieces It at the work loading and unloading station It may be intermittently returned to the tank Ilt after successive bodies thereof are collected in the cylinder I39.

As best shown in Figs. 2 and 9 to 12 inclusive,

the mechanism for rotating the carriage II and quench liquid to a definite level, as determined by indexing its movement, to advance each work piece from one station to a succeeding station, comprises the hydraulic cylinder 3| previously described and a cylindrical-shaped cam member I 42 and associated cam follower I43.

The cylindrical-shaped cam member I42 is flxed at its upper end to the bottom ring-shaped plate 35 of the carriage II and depends downwardly therefrom within the c-shaped member 84, as best shown in Fig. 2. Hence, the c-shaped member 84 thermally shields the cam member I42 from the high temperature heat developed at the heating stations I1 and I8. The cam member I42 is formed with a cam race of the general shape shown in Fig. 11. The cam follower I43 is mounted on the base structure It and positioned at the gap in the O-shaped member 84, as seen in Fig. 5, at a region removed from the heating stations I1 and It. The cam follower I43 comprises a rotatable roller fixed to a casting I44 which is rigidly mounted on an upright structural support I45 of the framework 2|, as best shown in Figs. 2 and 6, to provide a sturdy and rigid support for the cam follower I43, whereby the cam follower will be capable of withstanding the sudden thrusts of the relatively heavy carriage II to which it is subjected when the carriage is being rotated.

Referring more particularly to Figs. 9 to 12 inelusive, the cam race includes spaced apart vertical slots I48 which are closed at their upper ends and in open communication at their lower ends with inclined arms I41 and I48 forming V- shaped portions of the cam race. When the cylinder rod 29, upon which the carriage II is rotatably mounted, is in its lowermost position (Fig. 2), the cam follower I43 is positioned at the upper closed end of one of the vertical slots I46. When the cylinder rod 29 is actuated to move the carriage and advance the work pieces I5, the rotatable cam follower I43, which is held in a fixed position on the casting I44, prevents turning movement of the cylindrical-shaped cam member I42 and the carriage II to which it is fixed, because of its position in the vertical slot I46 of the cam race. Hence, the initial increment of movement imparted to the carriage I I, when the latter is raised or lifted from its lowermost position, is a straight upward movement with respect to the cam follower I43.

After the carriage II is raised vertically a definite distance, the cam follower I43 strikes the bottom edge of an inclined arm I41 of the cam race, as indicated at A in Fig. 12. when this occurs, the carriage II is still being raised by the hydraulic cylinder 3|, so that a turning or rotating movement is imparted to the cam member I42 and carriage II as the cam member I42 is being raised and the follower I43 is riding down the inclined arm I41 Of the V-shaped portion of the cam race.

At the juncture of the arms In and m of 1553 cam race, the hydraulic cylinder 3| reverses its stroke to lower the hydraulic cylinder rod 29 and carriage I I mounted thereon. When the cylinder rod 29 moves downwardly, the cam follower I43 strikes the top edge of an inclined arm I48 of the cam race and rides along such top edge, thereby continuing to impart a turning or rotating move-.

ment to the cylindrical cam member I42and carriage II to which it is fixed.

When the cylindrical cam member I42 turnspieces I6 from one station to a succeeding sta-' tion, is a straight downward movement. Such downward movement of the carriage I I is effected during the final portion of the downward stroke of the hydraulic cylinder rod 28 during which time the vertical slot I48 moves down over the cam follower I42 until the closed end of the slot is a short distance from the cam follower. The gap or space between the closed end of each vertical slot I44 and cam follower I42 is provided when the carriage II is in its lowermost position so that thecam follower will not be required to support any part of the weight of the carriage.

The cam race in the cylindrical cam member I42 is of such shape that, when the cam member I42 is being raised, the cam follower I 43 will always enter the upper end of an inclined arm I41 and cannot enter an arm I48 of the cam race from which it has previously emerged; and, when the cam member I42 is being lowered, the. cam follower I48 will always pass from an arm I48 into a vertical slot I48 and cannot pass directly into an arm I41 from an arm I48. This is accomplished by extending one side wall of each slot I48 downward a greater distance than its opposite side wall, as best shown in the developed view in Fig. 12. A portion of the longer side wall of each slot I46 in a sense overlaps the upper end of the arm I48 communicating therewith, so that, due to the angular momentum ofthe cam member I42 and carriage I I resulting from the turning move-.

ment imparted thereto, the longer side wall of each vertical slot I44 at its'bottom portion will strike the cam follower I43; and, since the cam member I 42 is being lowered at such time, the cam follower I48 can only enter the lower open end of the slot.

The bottom edges of the inclined arms I41 at their upper parts are directly beneath the lower open ends of the slots I44. Hence, when the cam member I42 and carriage II are being raised, the -cam follower I42 passes directly from each vertical slot I48 onto the bottom edge portion of an arm I41 extending and projecting under the lower open end of the vertical slot. Since this initial increment of vertical movement is imparted to the cam member I42 and carriage I I from a stop position of the latter, the cam follower I42 under no circumstance can pass into the upper end of the arm I48 from which it has previously emerged.

It will be noted in Fig. 12 that the bottom portions of the inclined arms I48 of the cam race are widened considerably with respect to the width of the cam race at the upper portions of these arms. It was found that, by' properly adjusting the timing of the up strokes and down strokes of the hydraulic cylinder rod 28 and providing such widened portions in the cam race, the fixed rotatable cam follower I43, upon emerging from the lower ends of the inclined arms I41, would avoid striking the extreme bottom end portions of the cam race; and, after passing from each arm I 41, next contact and position C in Fig. 12.

When the cam member I42 and carriage II are being raised and the cam follower I43 rides engage the cam race at the against the bottom edge of an arm I41, a turning movement is imparted to the cam member and.

against the bottom edge of the inclined arm I41 of the cam race. By providing the widened gaps at the bottom portions of the inclined arms I41 and reversing the stroke of the hydraulic cylinder II while the cam follower I 43 is in such gaps, the cam follower will next engage the top edges oi the arms I48 at the position C in Fig. 12. At the position C the cam follower I42 engages an inclined surface along which it can freely ride to continue imparting a turning movement to the cam member I42, without requiring the cam follower I42 to bring the carriage II and cylindrical cam member I42 to a complete stop when the hydraulic cylinder rod 28 reaches the upper limit of its stroke and starts moving downward again.

A control mechanism suitable for operating the hydraulic cylinder Si is more or less diagrammatically shown in Fig. 13. The control mechanism illustrated provides an arrangement for alternately supplying a fluid, such as oil, for example, to the regions above and below the piston 28 in the hydraulic cylinder 3|, to raise and lower the carriage II intermittently and thus advance and index the movement of the work pieces I6 from one station to a succeeding station.

In Fig. 13 oil is pumped from a reservoir I50 through a conduit III by a pump I52, the outlet of which is connected to a conduit i53 in which is provided a pressure relief valve I54, :3, check valve I" for adjusting the oil delivery pressure, and a pressure gauge I58. A by-pass conduit I51 connects the pressure relief valve I54 to the upper part of the reservoir I 58.

A valve mechanism I 58 comprises a shell or housing formed to provide a central chamber I59 into which oil is discharged from the conduit I53. and side chambers I68, I6I, I62 and I 63 at each side of the central chamber. A shaft I64, to which a number of valves I65a, I65b, Iii-"u: and I8 are secured, extends through the valve mechanism housing.

58 When the shaft I84 is-in the left-hand position shown in Fig. 13, oil is discharged from the conduit is: into the central'chamber I59 and passes into chamber I8I from which it is discharged through a conduit I66 to the bottom of Q the cylinder SI below the piston 30. .Under these conditions the piston 38 is caused to rise, thereby raising the hydraulic cylinder rod 29 and carriage II mounted thereon to which the cylindrical cam member I42 is secured.

I As the piston 28 is being raised in the cylinder 8|, the oil above the piston is forced out of the cylinder through a conduit I61 into chamber I60 and thence into the chamber I62 from which the oil passes into a conduit I68 and returns to the reservoir I58. While oil passing into conduit I68 can return to the reservoir I56, such oil cannot pass into the chamber I 6| because the valve :31! prevents flow of oil therein from chamber When the shaft I44 is shifted to its right-hand ber I58 from chamber I6I, and valves I85b and I85d are within the chambers I58 and I58, respectively.

In such right-hand position of the shaft I84, oil under pressure can only pass from the central chamber I58 into chamber I68 and flow therefrom through conduit I61 into the upper part of cylinder 8| above the piston 88. Under these conditions the piston 88 is moved downwardly, thereby lowering the hydraulic cylinder rod 28 and carriage II mounted thereon to which the cam member I42 is fixed.

As the piston 88 is being lowered in the cyiin der H, the oil below the piston is forced out of the cylinder through conduit I66 into chamber "I and thence into chamber I68 from which the oil passes into conduit I68 and returns to the reservoir I58. The oil being returned to the reservoir I50 through conduit I68 from the chamber I68 cannot pass into chamber I68 because the valve I651: prevents flow of oil into that chamber from chamber I62.

To cause the shaft I64 to move back and forth between the left-hand position illustrated in Fig. 13 and the right-hand position just described, a pair of electromagnets I68 and I18 are provided at the ends of the shaft through which the end portions thereof extend. The electrolmagnets I68 and I18 are connected to a suitable source of supply of electrical energy through circuit means including conductors "I and I12.

The conductor "I is connected through conductor I18 to one terminal of electromagnet I68 and through another conductor I14 to one terminal of electromagnet I18. The conductor I12 is connected to acontact arm I15 which is adapted to move between stationary contact arms I16 and I11 and is held in its upper closed position against the contact arm I16 by a spring I18 having one end thereof connected to an insulatin sleeve member I18 on the contact arm I15 and the opposite end thereof secured to a fixed support I88. The contact arm I15 is also connected to a downwardly depending plunger I8I of a solenoid I82 which, when energized, causes the contact arm I15 to move downwardly against the action of spring I18 and close contact arms I15 and I11.

When the contact arm I15 is in its upper position to close contact arms I16 and I11, a, circuit is completed through conductor I88 for the electromagnet I18 to cause the shaft I64 to shift to its right-hand position described above; and, conversely, when the solenoid I82 is energized and the contact arms I15 and I11 close, a circuit is then completed through conductor I84 for the electromagnet I68 to cause the shaft I54 to shift to its illustrated left-hand position. The solenoid I82 is connected by conductors I85 and I86 to conductors "I and I12, respectively. A suitable time operated switch I81 is connected in conductor I86 whereby the circuit for the solenoid I82 is intermittently closed and opened for desired intervals of time.

The shaft I64 may be Journaled in any suitable manner at the ends of the valve mechanism housing and suitable stops I88 and I88 may be provided on the shaft which are engaged by abutments on the latter to limit the extent of axial movement imparted to the shaft. In this way the valves I650, I651), I650 and I65d will be properly positioned at the end of each stroke of 18 depending upon whether electromagnet I88 01' electromagnet I18 is energized.

The control mechanism for the hydraulic cylinder I82 at the quench station Itis generally similar to that just described for the hydraulic cylinder 8|. As more or less diagrammatically shown in Fig. 14, the control illustrated comprises a valve mechanism I581: generally like that seen in Fig. 13 in which similar parts are referred to by like reference numerals. The valve mechanism I 58a in Fig. 14 operates to supply oil underpressure either below or above a piston I88 to which the rod I88 is fixed to cause the latter to move alternately upward and downward.

The oil circulating system provided for the main hydraulic cylinder 8i and shown in Fig. 13 may be employed for the valve mechanism 858s in Fig. 14. Thus, the oil delivered to the main central chamber I58 of the valve mechanism I58a in Fig. 14 may be delivered thereto under pressure through a conduit I58a which is connected to the conduit I58 in Fig. 13 between the check valve I and the pressure relief valve I54. Similarly, oil may be returned from the valve mechanism I58a in Fig. 14 through a con= duit I861: connected to the upper part of the reservoir I58, as shown in Fla. 13. The operation of the valve mechanism I58a in Fig. 14 is similar to that described in connection with Fig. 13 and will not be repeated here.

The control mechanism of Fig. 14 differs from that shown in Fig. 13 in that the shaft I54a is caused to move to its left-hand position by an electromagnet I580; and, when the electromagnet is deenergized, the shaft is caused to move to its right-hand position by the action of a spring Ill.

The electromagnet I68a is connected to a source of supply of electrical energy through circuit means including conductors "Ia and I12a. The conductor I1Ia is connected through a conductor I18a to one terminal of the electromagnet I68a, and the conductor I12a is connected to a stationary contact arm I15a. The contact arm I151: is adapted to move between a contact arm I11a and a stop I82 and is held in its upper position against the stop I82 by a spring I18a having one end thereofconnected to an insulating sleeve member I18a on the contact arm H511 and the opposite end thereof secured to a fixed support I88a. The contact arm "la is also connected to a downwardly depending plunger I8Ia of a solenoid I82a which, when energized, causes the contact arm H511 to move downwardly against the action of spring H84: and close contact arms I15a and I11a.

When the solenoid I82a is energized and contact arms I15a and I11a close, a circuit is then completed through conductor I84a for the electromagnet I68a to cause the shaft I64a to shift to its illustrated left-hand position against the action of spring I8I. When the electromagnet I68a is deenergized, the shaft I8'4a is caused to shift to its right-hand position by the action of the spring I8I. As in the control system illustrated in Fig. 13, solenoid I82a is connected by conductors I85a and I86a to conductors "Ia and I12a, respectively. A suitable time operated switch I81a is connected in conductor I88a whereby the circuit for the solenoid I82a is inter mittently closed and opened for desired intervals of time.

In view of the foregoing. it will now be understood that an improved heat treating machine has been provided for heat treating and hardenthe shaft I64, either to the left or to the right, 78 lng similar or like metallic work pieces in rapid 19. succession. Only a single operator or attendant is required at th work loading and unloading station I6 to remove from the work supporting fixtures I! the heat treated work pieces which move to that station and to position fresh work pieces on the fixtures I4 before the carriage moves to advance the fixtures to the next station. In the instant embodiment of the invention the work pieces I5 by way of example are of annular form and shown as ring gears. Such ring gears are formed of ferrous metal and provided with teeth at the outer peripheral surfaces thereof. The two heating stations I1 and I8 are provided to apply high temperature heat in two stages directly against the teeth at the outer peripheral surfaces thereof. At the first heating station I I heat is applied to bring the teeth to an elevated temperature below the critical hardening range, and at the second station I8 heat is rapidly applied to the outer peripheral-surfaces of the ring gears to bring these surfaces of the teeth to the 20 the cylinder rod I33, the solenoid I 82 becomes deenergized by proper adjustment of the time operated switch Il'la, so that the cylinder rod I33 will move downward immediately and permit thev desirable when it is possible to utilize the residual heat in a work piece, as in the inner portion of a ring gear, for example, to reheat. the outer toothed portions to a temperature approaching that used for tempering. In this way stresses in the outer hardened portions of the ring gears are relieved without the necessity of reheating the ring gears in a separate furnace to efiect tempering of the hardened work pieces. It is to be understood, however, that the hydraulic cylinder I32 may be omitted when not found necessary and that each work piece may remain in the body of quench liquid during the entire interval of time the carriage II is stationary.

At the cooling station 20 the work pieces I5 are supported by the work supporting fixtures I4 at the plate I34 provided on the pan I35 which partially covers one end of the quench tank H6.

rapidly cooled below the critical hardening temperature to effect the desired hardening of the work pieces. By providing the spray device II8 beneath the liquid level III.in the tank H6 and supplying quench liquid thereto under pressure, any vapor film tending to form at the outer peripheral surfaces of the ring gears is effectively broken up and the desired turbulent movement of the quench liquid is produced and promoted at vicinities closely adjacent to the outer peripheral surface areas of the ring gears at which maxtionary. The exact moment when the hydraulic cylinder I32 becomes operable to lift the quenched work pieces out of the body of quench liquid in the tank II6 can be accurately adjusted by proper regulation of the time operated switch I8la embodied in the control mechanism for the hydraulic cylinder I32 and shown in Fig. 14.

In order to maintain each work piece in its raised position at the quench station I9 after the hydraulic cylinder I32 is actuated to cause the cylinder I33 to move upward, the time operated switch IBM in Fig. 14 is so adjusted that the solenoid I82a will remain energized until the car riage II has moved upward a suflicient distance for the enlarged head 63 of the spindle 51 at the quench station to engage the bearing 60. When this occurs the raised work piece at the quench station I9 is then carried by the carriage from its raised position to the cooling station 20.

Immediately after the raised work piece at the quench station I9 is lifted from the upper end of Quench liquid from thework pieces I5 at the cooling station 20 drips onto the downwardly sloping pan I35 and returns by gravity to the quench tank II6. After being air cooled at the cooling station 20, the work pieces are then advanced to the work loading and unloading station It at which station the heat treated and hardened work pieces are removed from the work supporting fixtures I3. The desired intermittent movement of'the carriage II can be accurately adjusted by regulation of the time operated switch IB'Iv embodied in the control mechanism for the hydraulic cylinder 3I and shown in Fig. 13. Each upward stroke and subsequent downward stroke of the cylinder rod 29 raises the carriage II from the position shown in solid line to the dotted line position in. Fig. 1 and back to the position illustrated. Each pair of upward and downward strokes of the cylinder rod 29 constitutes a complete cycle of vertical movement necessary to move the carriage II such an angular distance that the work supporting fixtures are carried from one station to a succeeding station. The desired movement of the carriage is effected, as previously explained, by the cylindrical cam member I42 and cam follower I43-associated therewith. I

By carrying the work supporting fixtures I4 from each station to a succeeding station in a path of movement in which the initial increments of movement are more or less straight upward and the final increments of movement are more or less straight downward, the heating stations I1 and I8 may be formed as shown and described above to completely encircle the work pieces I5 at close range; that is, the gaps at the heating stations between the work pieces I5 and the restricted outlets 99 of the heating units 92 are relatively small and in the order of one-fourth inch or less. By providing relatively small gaps at the heating stations I1 and I8 between the outer peripheral surfaces of the work pieces I5 and the sources of high temperature heating gases discharged through the restricted outlets 99, rapid heating of the work pieces is effected. Moreover, by driving the work supporting fixtures I4 so that the work pieces II are rapidly turned and rotated while being heated, substantially uniform heating of the entire outer peripheral surfaces 01' the work pieces II is effected.

While a single embodiment oi the invention has been shown and described, it will be apparent to those skilled in the art that modifications and changes may be made without departing from the spirit and scope of the invention. For example, the cooling station 20 may in some cases be omitted and the work pieces II advanced directly from the quench station It to the work loading and unloading station It. We therefore do not wish to be limited to the embodiment shown in the drawings and described in the specification and aimin the following claims to cover all or the modifications and changes which fall within the true spirit and scope of the invention.

What is claimed is: a

l. Apparatus for heat treating metallic work pieces comprising structure providing a number of spaced apart stations for the work pieces ineluding a work loading and unloading station and other stations at which the work pieces are heated and cooled, a carriage having mounted thereon a plurality of spaced apart work supporting fixtures for the work pieces, means for supporting said carriage for rotation, means for bod ly raising and lowering said carriage, means attached to said carriage operable, when the latter is raised and lowered, to rotate said carriage on its supporting means to carry each work supporting fixture from one station to a succeeding station, driving means mounted on said carriage to rotate said fixtures, and means operable to disconnect from said driving means each work supporting fixture only while it is at the work loading and unloading station.

2. Apparatus for heat treating metallic wor pieces comprising structure providing a number oi stations including one or more heating stations in spaced apart-relation, a carriage having mounted thereon a plurality of spaced apart work supporting fixtures for the work pieces, means for intermittently moving said carriage to carry the work supporting fixtures successively from one station to a succeeding station, said moving means comprising mechanism to raise andwlower said carriage bodily and means to rotate the lat- .ter as it is being raised and lowered to move each work supporting fixture from one station to a succeeding station in a path of movement which includes an initial increment of movement which is generally upward and a final increment oi movement which is generally downward, driving means mounted on said carriage to rotate said tatable carriage including a plurality of spaced apart rotatable work supporting fixtures for the work pieces, means for intermittently moving said carriage to carry the work supporting fixtures successively from the work loading and unloading station to said one or more heating stations and to said quench station and finally back to the work loading and unloading station, said moving means comprising mechanism to raise and lower said carriage bodily and means to rotatethe latter to move each 'work supporting fixture from one station to a succeeding station in a path of movement which includes an initial increment oi movement which is generally upward and a final increment of movement which is generally downward, driving means mounted on said carriage for rotating said work supporting fixtures, and means operable to disconnect the fixtures from the driving means while the fixtures are positioned at the work loading and unloading station.

4. Apparatus for heat treating metallic work pieces comprising structure providing a number of spaced apart stations for the work pieces inseluding one or more stations at which the workpieces ar heated, a carriage having mounted thereon a plurality of spaced apart rotatable work supporting fixtures for the work pieces, means for rotatably supporting said carriage, means for raising and lowering said carriage, cam meansassociated with said carriage operable, when the latter is raised and lowered, to impart movement to said carriage to carry each work supporting fixture from one station to a succeeding station, driving means including an electric motor mounted on said carriage for rotating said work supporting fixtures, means to energize said motor including a slip ring plate movable with said car riage, a brush plate whose brushes are adapted to be connected to a source of electrical supply and arranged to bear against said slip ring plate, and means for supporting said brush plate in a manner to prevent angular movement thereof and permit vertical movement with vertical movement oi said carriage.

5. Apparatus for heat treating metallic work pieces comprising structure providing a number 01' stations including a work loading and unloading station and one or more heating stations and a quench station in spaced apart relation, a rotatable carriage having mounted thereon a plurality oi spaced apart rotatable work supporting fixtures for the work pieces, means for intermittently moving said carriage to carry the work supporting fixtures successively, from the work loading and unloading station to said one or more heating stations and to said quench station and finally back to th work loading and unloading station, said moving means comprising mechanism to raise and lower said carriage and means to rotate the latter to move each work supporting fixture from one station to a succeeding station in a path of movement which includes an initial increment of movement which is generally upward and a final increment of movement which is generally downward, driving means including,

an electrical motor mounted on said carriage for rotating said work supporting fixtures, means to energize said motor including a slip ring member movable with said carriage, a brush member whose brushes are adapted to be connected to a source of electrical supply and arranged to bear against said slip ring member, and means for supporting said brush member in a manner to prevent angular movement thereof and permit vertical movement with vertical movement of said carriage.

6. Apparatus for heat treating metallic work pieces comprising structure providing a number of stations including a work loading and unload-. ing station and one or more heating stations and a quench station in spaced apart relation, a rotatable carriage comprising a number of radially extending arms and work supporting fixtures depending from the outer ends oi. such arms for the v i work pieces, means for intermittently moving said carriage to carry the work supporting fixtures successively from the work loading and un-.

loading station to said one or more heating stations and to said quench station and finally back to the work loading and unloading station, said moving means comprising structure constructed and arranged to raise and lower said carriage as well as rotate the latter to move each work supporting fixture from one station to a succeeding station in a path of movement including an initial increment of movement which is generally upward and a final increment of movement which is generally downward, an annular-shaped vessel mounted on said carriage and open at the top. means for supplying cooling liquid to the vessel, said arms at least at the vicinities of said work supporting fixtures having hollow walls provided with inlets and outlets, means to conduct cooling liquid by gravity from said vessel to the inlets of said hollow walls, and means communicating with the outlets for carrying away liquid from the carriage.

7. Apparatus for heat treating metallic work pieces comprising structure providing a number of spaced apart stations for the work pieces ineluding one or more stations at which the work pieces are heated, a carriage comprising a number of radially extending arms and work supporting fixtures depending from such arms for the work pieces, means for rotatably supporting said carriage, means for raising and lowering said carriage, means associated with said carriage operable, when the latter is raised and lowered, to impart movement to said carriage to carry each work supporting fixture from one station to a succeeding station, an annular-shaped vessel mounted on the carriage and open at the top, means for supplying cooling liquid to the vessel, said arms at least at the vicinities of the work supporting fixtures having hollow walls provided with inlets and outlets, means toconduct cooling liquid by gravity from said vessel to the inlets of said hollow walls, and means communicating with th outlets for carrying away liquid from the carriage.

8. Apparatus for heat treating metallic work pieces comprising structure providing a number of stations including one or more heating stations in spaced apart relation, a rotatable carriage comprising a number of radially extending arms and work supporting fixtures depending from the outer ends of such arms for the work pieces, means for intermittently moving said carriage to carry the work supporting fixtures successively from one station to a succeeding station, said moving means comprising tructure constructed and arranged to raise and lower said carriage as well as rotate the latter to move each work sup,- porting fixture from one station to a succeeding station in a path of movement including an initial increment of movement which is generally upward and a final increment of movement which is generally downward, an annular-shaped first vessel mounted on said carriage and open at the top, means including a stationary pipe for supplying cooling liquid to th vessel, said arms at least at the vicinities of said work supporting fixtures having hollow walls provided with inlets and outlets, a second stationary annular-shaped vessel open at the top and positioned beneath said radially extending arms, means to conduct liquid by gravity from said first vessel to the inlets of said hollow walls, means including piping communicating with the outlets and movable with the carriage for conducting liquid from said hollow walls to said second vessel, and means for flowing cooling liquid from said second vessel.

9. Apparatus for heat treating metallic work' pieces comprising structure providing a number of stations including one or more heating stations in spaced apart relation, a rotatable carriage comprising a number of radially extending arms and work supporting fixtures depending from the outer ends of such arms for the work pieces, means for intermittently moving said carriage to carry the work supporting fixtures successively from one station to a succeeding station, said moving means comprising structure constructed and arranged to raise and lower said carriage as well as rotate the latter and move each work supporting fixture from one station to a succeeding station in a path of movement which includes an initial increment of movement which is generally upward and a final increment of movement which is generally downward, an annular-shaped vessel mounted on said carriage and open at the top, means including a stationary vertically disposed pipe having the lower end thereof positioned to supply liquid to the first vessel, said arms at least at the vicinities of said work supporting fixtures having hollow walls provided with inlets at one level and outlets at a higher level, means to conduct liquid by gravity from said vessel to the inlets of said hollow walls and means communicating with the outlets for removing from the carriage liquid overflowing from the hollow walls.

10. Apparatus for heat treating metallic work pieces comprising structure Providing a number 01 stations including one or more heating stations in spaced apart relation, a rotatable carriage comprising a number of radially extending arms and rotatable work supporting fixtures depending from the outer ends of such arms for the work pieces, means for intermittently moving said carriage to carry the work supporting fixtures successively from one station to a, succeeding station, said moving means comprising structure constructed and arranged to raise and lower said carriage as well as rotate the latter to move each work supporting fixture from one station to a succeeding station, mounted on said carriage and open at the top, means for supplying cooling liquid to the vessel including a stationary vertically disposed pip having the lower end thereof positioned to supply liquid to the vessel, said arms at least at the vicinities of said work supporting fixtures having hollow walls provided with inlets and outlets, means to conduct liquid by gravity from said vessel to the inlets of said hollow walls, and driving means mounted on said carriage for rotating said work supporting fixtures.

11. Apparatus for heat treating metallic work pieces comprising structure providing a number of stations including one or more heating stations and a quench station in spaced apart relation, a carriage having mounted thereon a plurality of spaced apart vertically movable work supporting fixtures for the work pieces, and means for intermittently moving said carriage to carry the work supporting fixtures from one station to a succeeding station, said moving means comprising mechanism to raise and lower said carriage and means to rotate the latter to move each work supporting fixture from one station to a succeeding station in a path of movement which includes an initial increment of movement which is generally upward and a final increment of movement which is generally downward, said quench station comprising a vessel adapted to hold a body of quench liquid into which the heated work pieces are adapted to be submerged by the work supporting fixtures,

an annular-shaped vessel 

